1. Field
The instant invention relates to dual-belt or dual-band filter presses employing multiple primary dewatering rolls or drums.
2. Prior Art
The filtering or dewatering of sewage, sludge and various other filter cake materials laden with water is conventionally accomplished through use of dual-belt or dual-band filters wherein the sludge is disposed between the two porous filter belts. The belts are passed around one or more primary rolls for the purpose of pressing the belts together to withdraw water through the belts and into the primary rolls or drums to dewater the filter cake. Such technique and apparatus are described in the following representative patents: U.S. Pat. No. 4,144,807 of Bastgen, entitled "Device For Dewatering Sludge"; U.S. Pat. No. 3,804,707 of Mohr et al, entitled "Papermaking Press With Inflatable Rolls Having Thin Deformable Outer Shells"; U.S. Pat. No. 4,159,947 of Brooks et al, entitled "Dewatering System"; U.S. Pat. No. 3,942,433 of Wohlfarter, entitled "Roller Arrangement in Presses For The Removal of Water From Materials"; U.S. Pat. No. 4,266,474 of Bahr, entitled "Chamber Type Filter Press For De-Watering Sludges And Similar Substances"; U.S. Pat. No. 4,053,419 of Pav, entitled "Band Filter Press"; U.S. Pat. No. 3,897,341 of Ozawa, entitled "Filter"; U.S. Pat. No. 3,906,853 of Wohlfarter, entitled "Roller Arrangement In Presses For the Removal of Water From Materials"; U.S. Pat. No. 3,951,805 of Dodd, entitled "Algae Harvester"; and U.S. Pat. No. 3,315,370 of Hikosaka, entitled "Continuous Dehydrating Apparatus".